Manufacturing of shoes for vehicle brakes

ABSTRACT

A bearing opening for the pivot pin in the web of the shoe of an internal shoe-drum brake is formed by piercing the web, extruding the web at the pierced hole, forming the extruded portion and finally machining the opening.

United States Patent [191 Mathers et al.

[ 4] MANUFACTURING 0F SHOES FOR VEHICLE BRAKES [75] Inventors: Robert Valentine Mathers, Chester; Derek Unsworth, Wrexham, both of England [73] Assignee: Rubery Owen-Rockwell, Limited,

Darlaston, England [22] Filed: Aug. 6, 1973 [21] Appl. No.: 385,879

[30] Foreign Application Priority Data Aug. 12, 1972 Great Britain 37694/72 [52] U.S. Cl. 29/l49.5 R, 29/DIG. 18 [51] Int. C11. B2ld 53/10 [58] Field 01 Search. 29/1495 R, 149.5 DP, 400 D, 29/DIG. l8, DIG. 47

[451 Feb. 11, 1975 [56] References Cited UNITED STATES PATENTS 1,272,051 7/1918 Kelley 29/1495 R 2,617,178 11/1952 Leake 29/1495 R X Primary Examiner-Thomas l-l. Eager Attorney, Agent, or Firm-Kemon, Palmer & Estabrook [57] ABSTRACT A bearing opening for the pivot pin in the web of the shoe of an internal shoe-drum brake is formed by piercing the web, extruding the web at the pierced hole, forming the extruded portion and finally machining the opening.

4 Claims, 2 Drawing Figures MANUFACTURING OF SHOES FOR VEHICLE BRAKES This invention relates to improvements in the manufacture of shoes for vehicle brakes.

The usual shoe for an internal shoe-drum brake comprises an arcuate flange carrying a friction lining and a web or two spaced parallel webs welded or otherwise secured to the flange.

In what are commonly called fixed shoe brakes each shoe pivots about one end on a pin fixed in the stationary backplate and the other end is engaged by a cam or other actuator for applying the shoe to a rotatable drum, the pivot pin passing through a bearing opening in the shoe web or webs. The web or each web is usually a sheet steel pressing or stamping.

Our invention is concerned with the formation of the bearing opening in a shoe web.

According to our invention a method of forming the bearing opening for the pivot pin in the web of a shoe of an internal shoe-drum brake comprises the steps of piercing the web at the required position, extruding the web at the pierced hole, forming the extruded portion to increase the thickness of the web around the opening, and finally machining the opening to suit the pivot pin. The forming operation is preferably carried out cold but hot forming can be used if preferred.

Part of the web of a shoe incorporating a pivot bearing opening formed in accordance with our invention is illustrated in the accompanying drawings in which:

FIG. 1 is an elevation of one end of a shoe web, and

FIG. 2 is a section on the line )(X of FIG. 1.

The web 1 of the shoe of an internal shoe drum brake has been formed at one end with a bearing opening 2. The upper surface in FIG. 2 of the part of the web surrounding the opening has been formed into a boss 3 which protrudes above the surrounding surfaces 4 of the web. The underside of the web around the opening 2 has been formed with a recess 5. The opening has been formed in the following way in a web which was initially in the form of a flat metal plate of substantially uniform thickness.

The metal has first been pierced with a sharp tool which has then been further forced through the web from one side, the underside in FIG. 2, to produce a funnel-shaped formation on the other side of the web. This formation has then been subjected to a cold coining operation between suitably shaped dies so as to form the boss 3 surrounding the opening. The overall thickness of the boss is, of course, greater than that of the undeformed web material. During the coining operation the underside of the web, in FIG. 2, has simultaneously been formed into the recess 5. Finally the opening has been machined to size, by drilling and reaming for example.

It will be appreciated that in a shoe having two spaced parallel webs the bearing hole in each web for the pivot pin will be formed in the same way.

We claim:

1. A method of forming the bearing opening for the pivot pin in the web of a shoe of an internal shoe-drum brake comprising the steps of piercing the web at the required position, extruding the web at the pierced hole, forming the extruded portion to increase the thickness of the web around the opening, and finally machining the opening to suit the pivot pin.

2. The method according to claim 1 in which each of the steps is carried out cold.

3. The method according to claim 1 in which the step of forming the extruded portion to increase the web thickness is carried out by cold coining of the extruded portion between dies.

4. The method according to claim 1 in which during the forming of the extruded portion to increase the web thickness the opposite side of the web to that bearing the protrusion is recessed slightly. 

1. A method of forming the bearing opening for the pivot pin in the web of a shoe of an internal shoe-drum brake comprising the steps of piercing the web at the required position, extruding the web at the pierced hole, forming the extruded portion to increase the thickness of the web around the opening, and finally machining the opening to suit the pivot pin.
 2. The method according to claim 1 in whIch each of the steps is carried out cold.
 3. The method according to claim 1 in which the step of forming the extruded portion to increase the web thickness is carried out by cold coining of the extruded portion between dies.
 4. The method according to claim 1 in which during the forming of the extruded portion to increase the web thickness the opposite side of the web to that bearing the protrusion is recessed slightly. 